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          Codeforces Div 2 天梯 21——25
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        <p><a target="_blank" rel="noopener" href="http://codeforces.com/problemset/problem/269/B">http://codeforces.com/problemset/problem/269/B</a> <span id="more"></span> 代码写起来还是很好写的，但是想到这个动态规划我确实想了一段时间... <span class="math inline">\(f_i\)</span> 代表点 <span class="math inline">\(i\)</span> 不动，前面的所有值都合法的最小移动距离 然后最后设一个肯定不动的点，记录一下最后结果就可以了 <figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span><span class="meta-string">&lt;bits/stdc++.h&gt;</span></span></span><br><span class="line"><span class="keyword">using</span> <span class="keyword">namespace</span> std;</span><br><span class="line"><span class="keyword">int</span> n,m;</span><br><span class="line"><span class="class"><span class="keyword">struct</span> <span class="title">pp</span></span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="keyword">int</span> s;</span><br><span class="line">	<span class="keyword">double</span> w;</span><br><span class="line">&#125; p[<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="function"><span class="keyword">bool</span> <span class="title">cmp</span><span class="params">(pp x,pp y)</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	<span class="keyword">return</span> x.w&lt;y.w;</span><br><span class="line">&#125;</span><br><span class="line"><span class="keyword">int</span> f[<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">()</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	cin&gt;&gt;n&gt;&gt;m;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		cin&gt;&gt;p[i].s;</span><br><span class="line">		cin&gt;&gt;p[i].w;</span><br><span class="line">		f[i]=<span class="number">2147483600</span>;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="built_in">sort</span>(p+<span class="number">1</span>,p+n+<span class="number">1</span>,cmp);</span><br><span class="line">	p[n+<span class="number">1</span>].s=m+<span class="number">1</span>;</span><br><span class="line">	f[n+<span class="number">1</span>]=<span class="number">2147483600</span>;</span><br><span class="line">	p[<span class="number">0</span>].s=<span class="number">0</span>;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n+<span class="number">1</span>;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">0</span>;j&lt;i;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="keyword">if</span>(p[j].s&lt;=p[i].s)</span><br><span class="line">			&#123;</span><br><span class="line">				f[i]=<span class="built_in">min</span>(f[i],f[j]+i-j<span class="number">-1</span>);</span><br><span class="line">			&#125;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	cout&lt;&lt;f[n+<span class="number">1</span>];</span><br><span class="line">	<span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure> <a target="_blank" rel="noopener" href="http://codeforces.com/problemset/problem/478/D">http://codeforces.com/problemset/problem/478/D</a> 题目倒是很好做...只是我的map一直被卡... 就是一个动态规划... <figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span><span class="meta-string">&lt;bits/stdc++.h&gt;</span></span></span><br><span class="line"><span class="keyword">using</span> <span class="keyword">namespace</span> std;</span><br><span class="line"><span class="keyword">int</span> mod;</span><br><span class="line">map&lt;<span class="keyword">int</span>,<span class="keyword">int</span>&gt; ha[<span class="number">900</span>];</span><br><span class="line">map&lt;<span class="keyword">int</span>,<span class="keyword">bool</span>&gt; vis[<span class="number">900</span>];</span><br><span class="line"><span class="keyword">int</span> r,g,t;</span><br><span class="line"><span class="keyword">int</span> f;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">ff</span><span class="params">(<span class="keyword">int</span> r,<span class="keyword">int</span> g,<span class="keyword">int</span> h)</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	<span class="keyword">if</span>(h==f) <span class="keyword">return</span> <span class="number">1</span>;</span><br><span class="line">	<span class="keyword">if</span>(vis[h][r]==<span class="number">1</span>) <span class="keyword">return</span> ha[h][r];</span><br><span class="line">	vis[h][r]=<span class="number">1</span>;</span><br><span class="line">	<span class="keyword">int</span> u=<span class="number">0</span>;</span><br><span class="line">	<span class="keyword">if</span>(r&gt;=h)</span><br><span class="line">	&#123;</span><br><span class="line">		u+=<span class="built_in">ff</span>(r-h,g,h+<span class="number">1</span>);</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">if</span>(g&gt;=h)</span><br><span class="line">	&#123;</span><br><span class="line">		u+=<span class="built_in">ff</span>(r,g-h,h+<span class="number">1</span>);</span><br><span class="line">	&#125;</span><br><span class="line">	u%=mod;</span><br><span class="line">	ha[h][r]=u;</span><br><span class="line">	<span class="keyword">return</span> u;</span><br><span class="line">&#125;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">()</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	mod=<span class="number">1e9</span>+<span class="number">7</span>;</span><br><span class="line">	cin&gt;&gt;r&gt;&gt;g;</span><br><span class="line">	<span class="keyword">for</span>(f=<span class="number">1</span>;f*(f+<span class="number">1</span>)/<span class="number">2</span>&lt;=r+g;f++);</span><br><span class="line">	cout&lt;&lt;<span class="built_in">ff</span>(r,g,<span class="number">1</span>);</span><br><span class="line">	<span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure> 然后不得已只能改成循环的模式... <figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span><span class="meta-string">&lt;bits/stdc++.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">define</span> maxx 211111</span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">define</span> mod 1000000007 </span></span><br><span class="line"><span class="keyword">using</span> <span class="keyword">namespace</span> std;</span><br><span class="line"><span class="keyword">int</span> f[maxx]=&#123;<span class="number">1</span>&#125;,ans;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">()</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	<span class="keyword">int</span> i,j,n,m,h;</span><br><span class="line">	cin&gt;&gt;n&gt;&gt;m;</span><br><span class="line">	<span class="keyword">for</span>(h=<span class="number">1</span>;h*(h+<span class="number">1</span>)/<span class="number">2</span>&lt;=n+m;h++); h--;</span><br><span class="line">	<span class="keyword">for</span>(i=<span class="number">1</span>;i&lt;=h;i++)</span><br><span class="line">		<span class="keyword">for</span>(j=n;j&gt;=i;j--)</span><br><span class="line">			f[j]=(f[j]+f[j-i])%mod;</span><br><span class="line">	<span class="keyword">for</span>(j=<span class="built_in">max</span>(<span class="number">0</span>,h*(h+<span class="number">1</span>)/<span class="number">2</span>-m);j&lt;=n;j++) ans=(ans+f[j])%mod;	</span><br><span class="line">	cout&lt;&lt;ans;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure> 上下两个程序的时间复杂度基本没什么变化...但是相差的常数确实有些难以接受... <a target="_blank" rel="noopener" href="http://codeforces.com/problemset/problem/375/B">http://codeforces.com/problemset/problem/375/B</a> 最开始的时候看错题了...写了一个悬线法极大子矩阵... <figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span><span class="meta-string">&lt;bits/stdc++.h&gt;</span></span></span><br><span class="line"><span class="keyword">using</span> <span class="keyword">namespace</span> std;</span><br><span class="line"><span class="keyword">int</span> h[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> l[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> r[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> ll[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> rr[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">bool</span> e[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> n,m;</span><br><span class="line"><span class="keyword">char</span> c;</span><br><span class="line"><span class="keyword">int</span> p;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">()</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	<span class="built_in">scanf</span>(<span class="string">&quot;%d%d&quot;</span>,&amp;n,&amp;m);</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">1</span>;j&lt;=m;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			cin&gt;&gt;c;</span><br><span class="line">			<span class="keyword">if</span>(c==<span class="string">&#x27;0&#x27;</span>) e[i][j]=<span class="number">0</span>;</span><br><span class="line">			<span class="keyword">else</span> e[i][j]=<span class="number">1</span>;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		p=<span class="number">0</span>;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">1</span>;j&lt;=m;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="keyword">if</span>(e[i][j]==<span class="number">0</span>) p=j;</span><br><span class="line">			ll[i][j]=p+<span class="number">1</span>; </span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		p=m+<span class="number">1</span>;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=m;j&gt;=<span class="number">1</span>;j--)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="keyword">if</span>(e[i][j]==<span class="number">0</span>) p=j;</span><br><span class="line">			rr[i][j]=p<span class="number">-1</span>;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">1</span>;j&lt;=m;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="keyword">if</span>(e[i][j]==<span class="number">1</span>)</span><br><span class="line">			&#123;</span><br><span class="line">				<span class="keyword">if</span>(e[i<span class="number">-1</span>][j]==<span class="number">0</span>)</span><br><span class="line">				&#123;</span><br><span class="line">					h[i][j]=<span class="number">1</span>;</span><br><span class="line">					l[i][j]=ll[i][j];</span><br><span class="line">					r[i][j]=rr[i][j];</span><br><span class="line">				&#125;</span><br><span class="line">				<span class="keyword">else</span></span><br><span class="line">				&#123;</span><br><span class="line">					h[i][j]=h[i<span class="number">-1</span>][j]+<span class="number">1</span>;</span><br><span class="line">					l[i][j]=<span class="built_in">max</span>(ll[i][j],l[i<span class="number">-1</span>][j]);</span><br><span class="line">					r[i][j]=<span class="built_in">min</span>(rr[i][j],r[i<span class="number">-1</span>][j]);</span><br><span class="line">				&#125;</span><br><span class="line">				<span class="comment">//cout&lt;&lt;i&lt;&lt;&quot; &quot;&lt;&lt;j&lt;&lt;&quot; &quot;&lt;&lt;h[i][j]&lt;&lt;&quot; &quot;&lt;&lt;l[i][j]&lt;&lt;&quot; &quot;&lt;&lt;r[i][j]&lt;&lt;endl;</span></span><br><span class="line">			&#125;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">int</span> ans=<span class="number">0</span>;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">1</span>;j&lt;=m;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			ans=<span class="built_in">max</span>(ans,(r[i][j]-l[i][j]+<span class="number">1</span>)*h[i][j]);</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="built_in">printf</span>(<span class="string">&quot;%d&quot;</span>,ans);</span><br><span class="line">	<span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure> 后来明确了题意之后，感觉是一个动态规划的问题... <span class="math inline">\(f_{ij}\)</span> 代表从i开始到j结束，这一段被覆盖了多少次... 然后可以在 <span class="math inline">\(O(N*M)\)</span> 的复杂度构建这个数组... 然后就可以求一下 <span class="math inline">\(f\)</span> 的后缀和，算一算就可以了 然后通过这个题，我发现scanf比getchar慢了好多啊... <figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span><span class="meta-string">&lt;iostream&gt;</span></span></span><br><span class="line"><span class="keyword">using</span> <span class="keyword">namespace</span> std;</span><br><span class="line"><span class="keyword">int</span> n,m;</span><br><span class="line"><span class="keyword">int</span> e[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> f[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> h[<span class="number">5010</span>][<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">int</span> q[<span class="number">5010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">char</span> c;</span><br><span class="line"><span class="keyword">int</span> l,r;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">()</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	<span class="built_in">scanf</span>(<span class="string">&quot;%d%d&quot;</span>,&amp;n,&amp;m);</span><br><span class="line">	<span class="built_in">scanf</span>(<span class="string">&quot;%c&quot;</span>,&amp;c);</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">1</span>;j&lt;=m;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			c=<span class="built_in">getchar</span>();</span><br><span class="line">			<span class="keyword">if</span>(c==<span class="string">&#x27;0&#x27;</span>) e[i][j]=<span class="number">0</span>;</span><br><span class="line">			<span class="keyword">else</span> e[i][j]=<span class="number">1</span>;</span><br><span class="line">		&#125;</span><br><span class="line">		<span class="keyword">if</span>(i!=n) <span class="built_in">scanf</span>(<span class="string">&quot;%c&quot;</span>,&amp;c);</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=<span class="number">1</span>;j&lt;=m;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="keyword">if</span>(e[i][j]==<span class="number">1</span>)</span><br><span class="line">			&#123;</span><br><span class="line">				<span class="keyword">if</span>(e[i][j<span class="number">-1</span>]==<span class="number">0</span>) l=j;</span><br><span class="line">				r=j;</span><br><span class="line">				<span class="keyword">if</span>(e[i][j+<span class="number">1</span>]==<span class="number">0</span>)</span><br><span class="line">				&#123;</span><br><span class="line">					<span class="keyword">for</span>(<span class="keyword">int</span> k=l;k&lt;=r;k++)</span><br><span class="line">					&#123;</span><br><span class="line">						f[k][r]++;</span><br><span class="line">						q[k]=<span class="built_in">max</span>(q[k],r);</span><br><span class="line">					&#125;</span><br><span class="line">				&#125;</span><br><span class="line">			&#125;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">int</span> ans=<span class="number">0</span>;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;=m;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">for</span>(<span class="keyword">int</span> j=q[i];j&gt;=i;j--)</span><br><span class="line">		&#123;</span><br><span class="line">			h[i][j]=h[i][j+<span class="number">1</span>];</span><br><span class="line">			h[i][j]+=f[i][j];</span><br><span class="line">			ans=<span class="built_in">max</span>(h[i][j]*(j-i+<span class="number">1</span>),ans);</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="built_in">printf</span>(<span class="string">&quot;%d&quot;</span>,ans);</span><br><span class="line">	<span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure></p>
<p><a target="_blank" rel="noopener" href="http://codeforces.com/problemset/problem/283/B">http://codeforces.com/problemset/problem/283/B</a> 在这道题中再一次见识到了memset的缓慢... 说实话，题目还是很简单的...动态规划 <span class="math inline">\(e_{i2}\)</span> 和<span class="math inline">\(e_{i3}\)</span> 代表从 <span class="math inline">\(x\)</span> 走到1或者结束游戏时候的 <span class="math inline">\(x\)</span> 值 <span class="math inline">\(p_{i2}\)</span> 和<span class="math inline">\(p_{i3}\)</span> 代表从 <span class="math inline">\(x\)</span> 走到1或者结束游戏时候的 <span class="math inline">\(y\)</span> 的变化值 <span class="math inline">\(t_{i2}\)</span> 和<span class="math inline">\(t_{i3}\)</span> 代表从 <span class="math inline">\(x\)</span> 走到1或者结束游戏时候的进行的步骤... 然后1的情况其实只有两种，每一个 <span class="math inline">\(i\)</span> 单独算一算就行了... 实现比较复杂吧...其实也还好，一遍就写对了，主要卡在了每次的memset...改一改就好了... <figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br><span class="line">106</span><br><span class="line">107</span><br><span class="line">108</span><br><span class="line">109</span><br><span class="line">110</span><br><span class="line">111</span><br><span class="line">112</span><br><span class="line">113</span><br><span class="line">114</span><br><span class="line">115</span><br><span class="line">116</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span><span class="meta-string">&lt;bits/stdc++.h&gt;</span></span></span><br><span class="line"><span class="keyword">using</span> <span class="keyword">namespace</span> std;</span><br><span class="line"><span class="keyword">bool</span> v[<span class="number">200010</span>][<span class="number">4</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">bool</span> w[<span class="number">200010</span>][<span class="number">4</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">long</span> <span class="keyword">long</span> e[<span class="number">200010</span>][<span class="number">4</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">long</span> <span class="keyword">long</span> p[<span class="number">200010</span>][<span class="number">4</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">short</span> t[<span class="number">200010</span>][<span class="number">4</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">long</span> <span class="keyword">long</span> a[<span class="number">200010</span>]=&#123;&#125;;</span><br><span class="line"><span class="keyword">long</span> <span class="keyword">long</span> n;</span><br><span class="line"><span class="class"><span class="keyword">struct</span> <span class="title">pp</span></span></span><br><span class="line"><span class="class">&#123;</span></span><br><span class="line">	<span class="keyword">long</span> <span class="keyword">long</span> e,p,t;</span><br><span class="line">&#125; u;</span><br><span class="line"><span class="function">pp <span class="title">ff</span><span class="params">(<span class="keyword">long</span> <span class="keyword">long</span> x,<span class="keyword">short</span> d)</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	pp o;</span><br><span class="line">	<span class="keyword">if</span>(x&lt;=<span class="number">1</span>||x&gt;n)</span><br><span class="line">	&#123;</span><br><span class="line">		o.e=x;</span><br><span class="line">		o.p=<span class="number">0</span>;</span><br><span class="line">		o.t=d;</span><br><span class="line">		<span class="keyword">return</span> o;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">if</span>(w[x][d]==<span class="number">1</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		o.e=<span class="number">-2147483644</span>;</span><br><span class="line">		w[x][d]=<span class="number">0</span>;</span><br><span class="line">		<span class="keyword">return</span> o;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">if</span>(v[x][d]==<span class="number">1</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		o.e=e[x][d];</span><br><span class="line">		o.p=p[x][d];</span><br><span class="line">		o.t=t[x][d];</span><br><span class="line">		<span class="keyword">return</span> o;</span><br><span class="line">	&#125;</span><br><span class="line">	v[x][d]=<span class="number">1</span>;</span><br><span class="line">	w[x][d]=<span class="number">1</span>;</span><br><span class="line">	<span class="keyword">if</span>(d==<span class="number">2</span>)</span><br><span class="line">	&#123;</span><br><span class="line">		o=<span class="built_in">ff</span>(x-a[x],<span class="number">3</span>);</span><br><span class="line">		e[x][d]=o.e;</span><br><span class="line">		p[x][d]=o.p+a[x];</span><br><span class="line">		t[x][d]=o.t;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">else</span></span><br><span class="line">	&#123;</span><br><span class="line">		o=<span class="built_in">ff</span>(x+a[x],<span class="number">2</span>);</span><br><span class="line">		e[x][d]=o.e;</span><br><span class="line">		p[x][d]=o.p+a[x];</span><br><span class="line">		t[x][d]=o.t;</span><br><span class="line">	&#125;</span><br><span class="line">	o.e=e[x][d];</span><br><span class="line">	o.p=p[x][d];</span><br><span class="line">	o.t=t[x][d];</span><br><span class="line">	w[x][d]=<span class="number">0</span>;</span><br><span class="line">	<span class="keyword">return</span> o;</span><br><span class="line">&#125;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">()</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	<span class="built_in">scanf</span>(<span class="string">&quot;%I64d&quot;</span>,&amp;n);</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">2</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="built_in">scanf</span>(<span class="string">&quot;%I64d&quot;</span>,&amp;a[i]);</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">2</span>;i&lt;=n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">if</span>(v[i][<span class="number">2</span>]==<span class="number">0</span>)</span><br><span class="line">		&#123;</span><br><span class="line">			u=<span class="built_in">ff</span>(i,<span class="number">2</span>);</span><br><span class="line">			e[i][<span class="number">2</span>]=u.e;</span><br><span class="line">			p[i][<span class="number">2</span>]=u.p;</span><br><span class="line">			t[i][<span class="number">2</span>]=u.t;</span><br><span class="line">		&#125;</span><br><span class="line">		<span class="keyword">if</span>(v[i][<span class="number">3</span>]==<span class="number">0</span>)</span><br><span class="line">		&#123;</span><br><span class="line">			u=<span class="built_in">ff</span>(i,<span class="number">3</span>);</span><br><span class="line">			e[i][<span class="number">3</span>]=u.e;</span><br><span class="line">			p[i][<span class="number">3</span>]=u.p;</span><br><span class="line">			t[i][<span class="number">3</span>]=u.t;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">long</span> <span class="keyword">long</span> ans;</span><br><span class="line">	<span class="keyword">long</span> <span class="keyword">long</span> r;</span><br><span class="line">	<span class="keyword">int</span> h;</span><br><span class="line">	<span class="keyword">for</span>(<span class="keyword">int</span> i=<span class="number">1</span>;i&lt;n;i++)</span><br><span class="line">	&#123;</span><br><span class="line">		a[<span class="number">1</span>]=i;</span><br><span class="line">		r=e[<span class="number">1</span>+a[<span class="number">1</span>]][<span class="number">2</span>];</span><br><span class="line">		<span class="keyword">if</span>(r==<span class="number">-2147483644</span>)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="built_in">printf</span>(<span class="string">&quot;-1\n&quot;</span>);</span><br><span class="line">			<span class="keyword">continue</span>;</span><br><span class="line">		&#125;</span><br><span class="line">		<span class="keyword">else</span> <span class="keyword">if</span>(r&lt;=<span class="number">0</span>||r&gt;n)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="built_in">printf</span>(<span class="string">&quot;%I64d\n&quot;</span>,p[<span class="number">1</span>+a[<span class="number">1</span>]][<span class="number">2</span>]+a[<span class="number">1</span>]);</span><br><span class="line">			<span class="keyword">continue</span>;</span><br><span class="line">		&#125;</span><br><span class="line">		<span class="keyword">else</span></span><br><span class="line">		&#123;</span><br><span class="line">			h=t[<span class="number">1</span>+a[<span class="number">1</span>]][<span class="number">2</span>];</span><br><span class="line">			<span class="keyword">if</span>(h==<span class="number">3</span>)</span><br><span class="line">			&#123;</span><br><span class="line">				<span class="built_in">printf</span>(<span class="string">&quot;-1\n&quot;</span>);</span><br><span class="line">				<span class="keyword">continue</span>;</span><br><span class="line">			&#125;</span><br><span class="line">			<span class="keyword">else</span></span><br><span class="line">			&#123;</span><br><span class="line">				<span class="built_in">printf</span>(<span class="string">&quot;%I64d\n&quot;</span>,p[<span class="number">1</span>+a[<span class="number">1</span>]][<span class="number">2</span>]+a[<span class="number">1</span>]+a[<span class="number">1</span>]);</span><br><span class="line">				<span class="keyword">continue</span>;</span><br><span class="line">			&#125;</span><br><span class="line">		&#125;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure> <a target="_blank" rel="noopener" href="http://codeforces.com/contest/329/problem/B">http://codeforces.com/contest/329/problem/B</a> 看了半天...我也没看懂题目... 然后就复制了一下... 似乎就是一个条件很多的广搜？... <figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;bits/stdc++.h&gt;</span></span></span><br><span class="line"><span class="keyword">using</span> <span class="keyword">namespace</span> std;</span><br><span class="line"></span><br><span class="line"><span class="keyword">int</span> mp[<span class="number">1009</span>][<span class="number">1009</span>],a[<span class="number">1009</span>][<span class="number">1009</span>];</span><br><span class="line">queue &lt;<span class="keyword">int</span>&gt; vx;</span><br><span class="line">queue &lt;<span class="keyword">int</span>&gt; vy;</span><br><span class="line"><span class="keyword">int</span> r,c;</span><br><span class="line"></span><br><span class="line"><span class="function"><span class="keyword">void</span> <span class="title">bfs</span><span class="params">(<span class="keyword">int</span> x,<span class="keyword">int</span> y,<span class="keyword">int</span> t)</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	<span class="keyword">if</span> (x&lt;<span class="number">0</span> || x==r || y&lt;<span class="number">0</span> || y==c || a[x][y]) <span class="keyword">return</span>;</span><br><span class="line">	<span class="keyword">if</span> (mp[x][y]==<span class="number">-1</span>) <span class="keyword">return</span>;</span><br><span class="line">	a[x][y]=t;</span><br><span class="line">	vx.<span class="built_in">push</span>(x+<span class="number">1</span>),vy.<span class="built_in">push</span>(y);</span><br><span class="line">	vx.<span class="built_in">push</span>(x),vy.<span class="built_in">push</span>(y+<span class="number">1</span>);</span><br><span class="line">	vx.<span class="built_in">push</span>(x<span class="number">-1</span>),vy.<span class="built_in">push</span>(y);</span><br><span class="line">	vx.<span class="built_in">push</span>(x),vy.<span class="built_in">push</span>(y<span class="number">-1</span>);</span><br><span class="line">&#125;</span><br><span class="line"></span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">()</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">	cin &gt;&gt; r &gt;&gt; c;</span><br><span class="line">	<span class="keyword">int</span> xx,yy;</span><br><span class="line">	<span class="keyword">for</span> (<span class="keyword">int</span> i=<span class="number">0</span>;i&lt;r;i++)</span><br><span class="line">		<span class="keyword">for</span> (<span class="keyword">int</span> j=<span class="number">0</span>;j&lt;c;j++)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="keyword">char</span> c;</span><br><span class="line">			cin &gt;&gt; c;</span><br><span class="line">			<span class="keyword">if</span> (c==<span class="string">&#x27;E&#x27;</span>) vx.<span class="built_in">push</span>(i),vy.<span class="built_in">push</span>(j);</span><br><span class="line">			<span class="keyword">else</span> <span class="keyword">if</span> (c==<span class="string">&#x27;S&#x27;</span>) xx=i,yy=j;</span><br><span class="line">			<span class="keyword">else</span> <span class="keyword">if</span> (c==<span class="string">&#x27;T&#x27;</span>) mp[i][j]=<span class="number">-1</span>;</span><br><span class="line">			<span class="keyword">else</span> mp[i][j]=c-<span class="string">&#x27;0&#x27;</span>;</span><br><span class="line">		&#125;</span><br><span class="line">	<span class="keyword">int</span> l=<span class="number">1</span>;</span><br><span class="line">	<span class="keyword">while</span> (vx.<span class="built_in">size</span>())</span><br><span class="line">	&#123;</span><br><span class="line">		<span class="keyword">int</span> s=vx.<span class="built_in">size</span>();</span><br><span class="line">		<span class="keyword">for</span> (<span class="keyword">int</span> i=<span class="number">0</span>;i&lt;s;i++)</span><br><span class="line">		&#123;</span><br><span class="line">			<span class="built_in">bfs</span>(vx.<span class="built_in">front</span>(),vy.<span class="built_in">front</span>(),l);</span><br><span class="line">			vx.<span class="built_in">pop</span>();</span><br><span class="line">			vy.<span class="built_in">pop</span>();</span><br><span class="line">		&#125;</span><br><span class="line">		l++;</span><br><span class="line">	&#125;</span><br><span class="line">	<span class="keyword">int</span> count=<span class="number">0</span>;</span><br><span class="line">	<span class="keyword">for</span> (<span class="keyword">int</span> i=<span class="number">0</span>;i&lt;r;i++)</span><br><span class="line">		<span class="keyword">for</span> (<span class="keyword">int</span> j=<span class="number">0</span>;j&lt;c;j++)</span><br><span class="line">			<span class="keyword">if</span> (a[i][j]&lt;=a[xx][yy] &amp;&amp; a[i][j]!=<span class="number">0</span> &amp;&amp; mp[i][j]&gt;<span class="number">0</span>) count+=mp[i][j];</span><br><span class="line">	cout &lt;&lt; count &lt;&lt; endl;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure></p>

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